The subject matter of the present disclosure broadly relates to the art of gas spring suspension systems and, more particularly, an extensible end member for use in forming with a gas spring assembly as well as a method of using the same.
The subject matter of the present disclosure finds particular application and use in conjunction with suspension systems of wheeled vehicles, and will be shown and described herein with reference thereto. However, it is to be appreciated that the subject matter of the present disclosure is also amenable to other applications and environments, and that the specific uses shown and described herein are merely exemplary. For example, the subject matter of the present disclosure could be used in support structures, height adjusting systems and actuators associated with industrial machinery, components thereof and/or other such equipment. Accordingly, the subject matter of the present disclosure is not intended to be limited to use associated with vehicle suspensions.
The problems associated with overextending a gas spring assembly such that the flexible wall thereof is tensioned between the opposing end members are generally well known. Such problems can include the undesirable formation of leak paths and the degeneration of otherwise substantially fluid-tight sealing arrangements. In some circumstances, one or more components of the gas spring assembly can even become damages or otherwise adversely effected. Accordingly, various arrangements have been proposed to prevent the occurrence of such overextension or to at least minimize the impact that such an event has on the structure and performance of the gas spring assembly.
One example of such an arrangement is shown in U.S. Pat. No. 6,402,128 ('128), which discloses an air spring having an end member, a main piston spaced from the end member, and a flexible wall secured therebetween in a conventional arrangement. The '128 patent also describes a restraining piston that is telescopically received within the main piston. An end of the restraining piston extends outwardly beyond the main piston and is secured to the end member. While various features of the restraining piston in the '128 patent provide other functional aspects of the air spring, the restraining piston also acts as a positive stop to prevent the flexible wall of the air spring from being tensioned and, thus, possibly damaged or otherwise adversely effected due to the occurrence of an overextended condition.
One difficulty with the foregoing and other known constructions that act to limit the distance that the end members of the air spring can be separated from one another is that in such constructions the length of the restraining piston will likely need to be related to the operative length of the flexible wall. That is, if the length of the restraining piston is significantly greater than the fully extended length of the flexible wall, the restraining piston could be ineffective in protecting against overextension of the flexible wall. Oppositely, if the length of the restraining piston is significantly less than the fully extended length of the flexible wall, the air spring could be incapable extending through the full functional range of the flexible wall. To ensure that complimentary components are used and optimal performance is attained, it may be necessary to use different restraining pistons for each of the different length flexible wall. It should be recognized that such arrangements can lead to increased production, assembly and inventory costs as well as other associated issues.
Another disadvantage of the foregoing and other known arrangements that act to limit the distance that the end members of the air spring can be separated from one another is that such extension-limiting devices are often formed within the spring chamber of the air spring. This can reduce the active surface area of the air spring and result in reduced load capacity thereof. As such, an air spring having a larger size (i.e., diameter) may be necessary to support the expected load conditions of a given application. While in some applications the operating envelope for an air spring may be sufficient to accommodate this increased size, in many applications operating envelopes are continuing to be reduced. As a result, it is generally desirable to avoid such increases in size.
Therefore, it is believed desirable to develop a piston assembly and gas spring assembly utilizing the same that is capable of overcoming the foregoing and other problems and disadvantages.